US5124209A - Paint film arrangement - Google Patents

Paint film arrangement Download PDF

Info

Publication number
US5124209A
US5124209A US07/452,831 US45283189A US5124209A US 5124209 A US5124209 A US 5124209A US 45283189 A US45283189 A US 45283189A US 5124209 A US5124209 A US 5124209A
Authority
US
United States
Prior art keywords
film
paint
paint film
intermediate coat
electrodeposition
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US07/452,831
Inventor
Hiroyuki Kishi
Hitoshi Kimura
Tsuneo Sakauchi
Katsuya Yamamoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nissan Motor Co Ltd
Original Assignee
Nissan Motor Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nissan Motor Co Ltd filed Critical Nissan Motor Co Ltd
Assigned to NISSAN MOTOR CO., LTD. reassignment NISSAN MOTOR CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: KIMURA, HITOSHI, SAKAUCHI, TSUNEO, YAMAMOTO, KATSUYA, KISHI, HIROYUKI
Assigned to NISSAN MOTOR CO., LTD. reassignment NISSAN MOTOR CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: KIMURA, HITOSHI, KISHI, HIROYUKI, SAKAUCHI, TSUNEO, YAMAMOTO, KATSUYA
Application granted granted Critical
Publication of US5124209A publication Critical patent/US5124209A/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09DCOATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/44Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications
    • C09D5/4473Mixture of polymers
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09DCOATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D167/00Coating compositions based on polyesters obtained by reactions forming a carboxylic ester link in the main chain; Coating compositions based on derivatives of such polymers
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/31504Composite [nonstructural laminate]
    • Y10T428/31511Of epoxy ether
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/31504Composite [nonstructural laminate]
    • Y10T428/31511Of epoxy ether
    • Y10T428/31515As intermediate layer
    • Y10T428/31522Next to metal
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/31504Composite [nonstructural laminate]
    • Y10T428/31678Of metal
    • Y10T428/31681Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/31504Composite [nonstructural laminate]
    • Y10T428/31786Of polyester [e.g., alkyd, etc.]

Definitions

  • This invention relates to improvements in a paint film arrangement coated on the outer panel of an automotive vehicle in order to increase the rust resistance for an edge of steel plate and the brightness of a coated paint film after completion of a finish coat.
  • a paint film arrangement for an automotive vehicle outer panel includes an electrodeposition paint film for the purpose of rust prevention, an intermediate coat paint film for the purpose of thickening the paint film arrangement, and a finish coat paint film for the purpose of colouring.
  • the automotive vehicle outer panel coated with such a paint film arrangement is required to have good smoothness, gloss and the like. Total evaluation of such characteristics has been usually accomplished by using a so-called PGD value which is measured by a PGD (Portable Gloss and Distinction) meter.
  • This PGD meter is, for example, a PGD-3 type one (produced by a Japan Colour Research Institute in Japan). It is known to those skilled in the art, that the PGD value becomes high as the smoothness and gloss of the finish coating film is higher.
  • the gloss depends on the performance of the finish coat paint film and seems to be an independent function of a finish coat paint. Concerning the smoothness, it is largely affected by the smoothness of under-coat films and therefore the electrodeposition paint film is eagerly required to have a good smoothness.
  • a so-called center line average height (roughness) Ra is usually used.
  • the center line average height Ra is measured by using a cutoff wavelength of 0.8 mm.
  • the center line average height Ra smaller than 0.3 ⁇ is usually used for conventional automotive vehicle electrodeposition paint film from the view point of external appearance.
  • an intermediate coat paint is designed to be intended to harden at a shorter time in order to ensure the smoothness on a horizontal plane and to prevent the smoothness from degrading due to run of paint during baking on a vertical plane.
  • the usual used intermediate coat paint has a hardening starting time not less than 12 minutes and less than 15 minutes, measured by an Oscillated Pendulum Analysis (OPA) with an oscillated pendulum type viscoelasticity measuring device.
  • OPA Oscillated Pendulum Analysis
  • the conventional paint film arrangement is formed by coating the intermediate coat paint having the hardening starting time (by the Oscillated Pendulum Analysis) less than 15 minutes, on the surface of the electrodeposition paint film having a center line average height not larger than 0.3 ⁇ .
  • the edge corrosion resistance is intended to be improved in the conventional paint film arrangement, it may be proposed to increase the viscosity of the electrodeposition paint film in a molten condition.
  • a measure to increase the concentration of pigment in the electrodeposition paint i.e., P(pigment)/B(binder) ratio
  • a measure to add non-molten type cross-linking resin particles i.e., a reology control agent
  • a measure to lower the hardening temperature to suppress flowing of the electrodeposition paint in a molten state under a cross-linking reaction a measure to lower the hardening temperature to suppress flowing of the electrodeposition paint in a molten state under a cross-linking reaction.
  • these measures largely degrade the flowability of the electrodeposition paint in a molten state.
  • the coated surface of the electrodeposition paint has a center line average height Ra not less than 0.3 ⁇ . Accordingly, in a case in which conventional intermediate and finish coats are formed on the thus formed electrodeposition paint film, the PGD value of the paint film arrangement on a horizontal plane largely lowers, thereby degrading a commercial value of the resultant automotive vehicle.
  • the inventors' researches and developments taking account of the above-discussed experimental results have found the following facts: In case of using an intermediate coat paint having a hardening starting time not more than 15 minutes measured by the OPA, the PGD value of the finish coat paint on a vertical plane is about the same as in the conventional paint film arrangement. Additionally, in the case of using an intermediate coat paint having the hardening starting time not less than 15 minutes, it is very high in an ability to erase a roughness not less than 0.5 mm in wave length, in the surface of the electrodeposition paint.
  • a paint film arrangement of the present invention is comprised of a film of an electrodeposition paint.
  • the surface of the film has a center line average height Ra within a range of 0.3 ⁇ Ra ⁇ 0.8 ⁇ .
  • the total of values of power spectrum within a wavelength range not less than 0.5 mm of the surface is not more than 80 ⁇ V2.
  • a film of an intermediate coat paint is formed on the surface of the electrodeposition paint film.
  • the intermediate coat paint film has a hardening starting time ranging from 15 to 20 minutes. The hardening starting time is determined according to a logarithmic decrement of viscoelasticity of the intermediate coat paint film by an oscilated pendulum type viscoelasticity measuring device.
  • the paint film arrangement of the present invention can be improved in both edge corrosion resistance of a steel plate and finished external appearance of the painted steel plate.
  • FIG. 1 is a graph showing total of values of power spectrum of an electrodeposition paint film forming part of a paint film arrangement according to the present invention.
  • FIG. 2 is a graph showing the relationship between time and logarithmic decrement, for the purpose of determining the hardening starting time t of an intermediate coat paint film forming part of the paint film arrangement according to the present invention.
  • a paint film arrangement is comprised of a film of an electrodeposition paint, the surface of the film having a center line average height Ra within a range of 0.3 ⁇ Ra ⁇ 0.8 ⁇ , total of values of power spectrum within a wavelength range not less than 0.5 mm of said surface being not more than 80 ⁇ V 2 ; and a film of an intermediate coat paint formed on the electrodeposition paint film, the intermediate coat film having a hardening starting time ranging from 15 to 20 minutes, said hardening starting time being determined according to a logarithmic decrement of the intermediate coat paint film by an oscillated pendulum type viscoelasticity measuring device.
  • the surface of the electrodeposition paint film necessarily has a center line average height Ra not less than 0.3 ⁇ , measured with a cutoff wavelength of 0.8 mm in order to obtain a high edge corrosion resistance.
  • the maximum value of the center line average height Ra must be suppressed at a value of 0.8 ⁇ .
  • the total ( ⁇ P 0 .5 mm>) of the power spectrums within the wavelength not more than 0.5 mm according to a surface frequency analysis is decided to be not more than 80 ⁇ V 2 .
  • the surface condition of the electrodeposition paint is defined by the above-mentioned two values Ra and ⁇ P 0 .5 mm> is that the surface condition of the intermediate paint film depends not only on a surface roughness value Ra but also on another surface roughness value ⁇ P 0 .5 mm>.
  • the values Ra are the same in two cases, the electrodeposition paint surface conditions after coating the intermediate coat paint film may be different from each other, and depends on the difference in the surface roughness value ⁇ P 0 .5 mm>.
  • the values Ra and ⁇ P 0 .5 mm> are evaluation criteria for surface roughness within different wavelength ranges.
  • the value Ra represents the surface roughness (average amplitude value) within a wavelength range from 0.8 to 0.5 mm
  • the value of ⁇ P 0 .5 mm> represents the surface roughness (total of the square of amplitude value of the respective wavelength).
  • the values Ra and ⁇ P 0 .5 mm are essential to find and define the feature of the surface profile of the coated paint film.
  • the value Ra is defined to be 0.8 ⁇ in maximum for the reasons set forth below.
  • the value Ra of the electrodeposition paint film surface is in a good interelationship to the hardening starting time of the intermediate coat paint film, measured by an Oscillated Pendulum Analysis (OPA). More specifically, in the case of an intermediate coat paint film (a conventional intermediate coat paint film) having the hardening starting time of 12 to 15 minutes, it is possible to smoothen the surface of the electrodeposition paint film surface having the surface roughness up to 0.3 ⁇ . In case of the intermediate coat paint film having the hardening starting time of 15 to 20 minutes, it is possible to smoothen the surface of the electrodeposition paint film surface having the surface roughness not less than 0.8 ⁇ .
  • OPA Oscillated Pendulum Analysis
  • the value Ra of the electrodeposition paint film is decided to be up to 0.8 ⁇ , and the hardening starting time of the intermediate coat paint film is decided to be within a range from 15 to 20 minutes.
  • the value ⁇ P 0 .5 mm> is decided to be not more than 80 ⁇ V 2 for the following reasons: Only the electrodeposition paint film having the surface roughness not more than 80 ⁇ V 2 can be smoothened with the intermediate coat paint having the hardening starting time ranging from 15 to 20 minutes. It will be understood that it is impossible to smoothen the electrodeposition paint film having the surface roughness over 80 ⁇ V 2 with the intermediate coat paint.
  • the center line average height Ra was measured with a cutoff wavelength of 0.8 mm by using a commercially available surface roughness tester and according to a test method of JIS (Japanese Industrial Standard) B0601.
  • the used tester was a Surfcom 550A produced by Tokyo Seimitsu Co., Ltd in Japan.
  • the power spectrum was able to be easily determined by combining the commercially available surface roughness tester and a FFT (Fast Fourier Transfer) analyzer.
  • the Surfcom 550A was combined with a commercially available VS 3321A type FFT analyzer produced by Matsushita Communication Industrial Co., Ltd. in Japan.
  • the power spectrum was determined under conditions of input sensitivity of wavelength: -20 dB, frequency: not more than 100 Hz, and data input number (FFT data processing number): 1,024 points. Measurement was made 10 times, and an average for the 10 measurements was determined to obtain the power spectrum.
  • ⁇ P 5 mm> was obtained by accumulating the values of the power spectrum within a wavelength not more than 0.5 mm which is a value obtained by dividing the frequency 1.2 Hz by a waveshape input rate (0.6 mm/s in this measurement).
  • the relationship between the spectrum value and the wavelength is shown in FIG. 1.
  • This determining method of the power spectrum and the accumulated value thereof are well known for a method of analyzing a surface profile of a paint film and was disclosed in a technical literature "Colouring Material Study Representation Summary (1985)" issued in Japan.
  • the viscoelasticity of the intermediate coat paint was measured by an oscillated pendulum type viscoelasticity measuring device (trade name "Rheo-Vibron DDV-OPA") produced by Orientec Corporation in Japan, under conditions of a weight: 22 g, moment of inertia: 859 g.cm 2 , and temperature rising rate: 20° C./min.
  • a time duration t between a time point of starting heating and a time point of starting in rise of a logarithmic decrement ⁇ of viscoelasticity as shown in FIG. 2 was determined to obtain the hardening starting time.
  • FIG. 2 illustrates a method for determining the hardening starting time t for the intermediate coat paint.
  • a variety of electrodeposition paints were prepared by changing the ratio of a low temperature hardening resin and the concentration of pigment to regulate the flowability in a molten state.
  • Epoxidated polybutadiene containing double bonds was used as the low temperature hardening resin and prepared as set forth below.
  • an epoxidated polybutadiene was prepared as follows: Low polymerization of butadiene was made at 30° C. in the presence of toluene (a chain transfer agent) using benzyl sodium as a catalyst, thereby to obtain liquid polybutadiene which had a number average molecular weight of 2000, a viscosity of 120 poise at 25° and 65% of 1,2-bond. The liquid polybutadiene was epoxidated with peracetic acid thereby to produce an epoxidated polybutadiene having an oxyrane oxygen content of 6.0% by weight.
  • the low temperature resin (the epoxidated polybutadiene containing double bonds) was prepared as follows: 1076 g of the epoxidated polybutadiene produced in the above-manner was mixed with 215 g of ethylcellosolve and supplied into a 2 liter autoclave. Thereafter, 50 g of dimethylamine was supplied into the autoclave. Then reaction was made at 150° C. for 5 hours. After unreacted amine was removed, a mixture of 83 g of acrylic acid, 7 g of hydroquinone and 27 g of ethylcellosolve was added into the autoclave. A further reaction was made at 150° C. for 45,minutes thereby producting a resin composition of the low temperature hardening resin having an amine value of 40 mgKOH/g, an acid value of 1 mg KOH/g and a solid concentration of 83.3% by weight.
  • An epoxy resin-acrylic acid addition resin for the purpose of controlling the ratio of the above mentioned low temperature hardening resin was prepared as follows: Bisphenol type epoxy resin (Epikote No. 1001, trade name of Shell Kagaku K.K. in Japan) having an epoxy equivalent of 500 was obtained by reaction between bisphenol A and epichlorohydrin and represented by the following chemical formula: ##STR1##
  • the thus produced resin solution of polyester resin modified by ⁇ -caprolactone was mixed with melamine resin, controlling a blending ratio (the resin solution/melamine resin).
  • the melamine resin was Cymel 303 (trade name of Mitsui Cyanamid Co., Ltd. in Japan).
  • the intermediate coat paint was prepared according to the detail shown in Table 2.
  • “Solvesso” is the trade name of a dilution thinner produced by Exxon Chemical Co., Ltd. and includes a high boiling point aromatic (petroleum) solvent as a major component.
  • “Surface controlling agent” is a silicone additive produced by Toray Dowcorning Silicone Co., Ltd.
  • Shot-dulled steel plates of SPCC (according to Japanese Industrial Standard) were chemically treated with PBL3020 (trade name of Nihon Parkerising Co., Ltd. in Japanese).
  • the above-mentioned sixteen kinds of electrodeposition paints were coated respectively on the chemically treated steel plates by electrodeposition in a manner to obtain a coat film thickness of 20 ⁇ m under conditions of paint liquid temperature: 28° C., electrodeposition time: 3 minutes, and impressed voltage: 150 to 200 V Thereafter, thus coated paints were subjected to baking at 175° C. for 30 minutes thereby to harden the coated paint films.
  • the above-mentioned intermediate paints of Production Nos. 17 to 19 were coated on the above sixteen kinds of electrodeposition-coated steel plates by spray-painting to have a coat film thickness of 30 to 40 um. After allowing the plates to stand for a predetermined time, baking was made at 140° C. for 30 minutes. Subsequently, the respective steel plates coated with the intermediate paints were further coated with an alkyd resin finish coat paint (Melami No. 1500 black: trade name of Nihon Oil & Fats Co., Ltd.) to have a paint film thickness of 35 to 40 um. Then baking was made for each steel plate with the finish coat.
  • an alkyd resin finish coat paint (Melami No. 1500 black: trade name of Nihon Oil & Fats Co., Ltd.)
  • the edge corrosion resistance in Table 3 was measured by the following method: A steel cutter knife blade (LB-10: trade name of OLFA Corporation in Japan) was chemically treated with PBL3020. Each of the above-mentioned sixteen kinds of electrodeposition paints was coated on the chemically treated knife blade and thereafter coated with the electrodeposition paint. Then, the coated electrodeposition paint was baked at 175° C. for 30 minutes. Thereafter the knife blades coated with the electrodeposition paints were subjected to a salt water spraying test of 200 hours. After the test, the number of rusted points at the edge section was counted as shown in Table 3.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Molecular Biology (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Laminated Bodies (AREA)
  • Paints Or Removers (AREA)

Abstract

A paint film arrangement formed on an outer panel of an automotive vehicle. The paint film arrangement comprises a film of an electrodeposition paint formed on the surface of a steel plate of the automotive vehicle outer panel. The surface of the electrodeposition paint film has a center line average height Ra within a range of 0.3μ≦Ra≦0.8μ. The total of values of power spectrum of the surface of the electrodeposition paint film is not more than 80 μV2 within a wavelength range not more than 0.5 mm. Additionally, a film of an intermediate coat paint is formed on the surface of the electrodeposition paint film. The intermediate coat paint has a hardening starting time ranging from 15 to 20 minutes. The hardening starting time is determined according to a logarithmic decrement of the intermediate coat paint by an oscillated pendulum type viscoelasticity measuring device.

Description

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to improvements in a paint film arrangement coated on the outer panel of an automotive vehicle in order to increase the rust resistance for an edge of steel plate and the brightness of a coated paint film after completion of a finish coat.
2. Description of the Prior Art
In general, a paint film arrangement for an automotive vehicle outer panel includes an electrodeposition paint film for the purpose of rust prevention, an intermediate coat paint film for the purpose of thickening the paint film arrangement, and a finish coat paint film for the purpose of colouring. The automotive vehicle outer panel coated with such a paint film arrangement is required to have good smoothness, gloss and the like. Total evaluation of such characteristics has been usually accomplished by using a so-called PGD value which is measured by a PGD (Portable Gloss and Distinction) meter. This PGD meter is, for example, a PGD-3 type one (produced by a Japan Colour Research Institute in Japan). It is known to those skilled in the art, that the PGD value becomes high as the smoothness and gloss of the finish coating film is higher. Here, the gloss depends on the performance of the finish coat paint film and seems to be an independent function of a finish coat paint. Concerning the smoothness, it is largely affected by the smoothness of under-coat films and therefore the electrodeposition paint film is eagerly required to have a good smoothness.
As a criterion for the smoothness, a so-called center line average height (roughness) Ra is usually used. The center line average height Ra is measured by using a cutoff wavelength of 0.8 mm. The center line average height Ra smaller than 0.3 μ is usually used for conventional automotive vehicle electrodeposition paint film from the view point of external appearance. In such a case, an intermediate coat paint is designed to be intended to harden at a shorter time in order to ensure the smoothness on a horizontal plane and to prevent the smoothness from degrading due to run of paint during baking on a vertical plane. In this regard, the usual used intermediate coat paint has a hardening starting time not less than 12 minutes and less than 15 minutes, measured by an Oscillated Pendulum Analysis (OPA) with an oscillated pendulum type viscoelasticity measuring device. Thus, the conventional paint film arrangement is formed by coating the intermediate coat paint having the hardening starting time (by the Oscillated Pendulum Analysis) less than 15 minutes, on the surface of the electrodeposition paint film having a center line average height not larger than 0.3 μ.
With the above-discussed paint film arrangement, in order to minimize the center line average height of the electrodeposition coat film, it is carried out to increase the flowability of the electrodeposition paint film during melting thereof. However, under the action of surface tension of the molten coat film at an edge portion of the steel plate of the automotive vehicle outer panel, the edge of the steel plate is exposed without the coat film, so that the above-discussed conventional paint film arrangement is inferior in a so-called edge corrosion resistance.
If the edge corrosion resistance is intended to be improved in the conventional paint film arrangement, it may be proposed to increase the viscosity of the electrodeposition paint film in a molten condition. For this purpose, there are proposed a measure to increase the concentration of pigment in the electrodeposition paint (i.e., P(pigment)/B(binder) ratio), a measure to add non-molten type cross-linking resin particles (i.e., a reology control agent) to the electrodeposition paint, and a measure to lower the hardening temperature to suppress flowing of the electrodeposition paint in a molten state under a cross-linking reaction. However, these measures largely degrade the flowability of the electrodeposition paint in a molten state. Assuming that these measures are taken to obtain a good edge corrosion resistance, the coated surface of the electrodeposition paint has a center line average height Ra not less than 0.3 μ. Accordingly, in a case in which conventional intermediate and finish coats are formed on the thus formed electrodeposition paint film, the PGD value of the paint film arrangement on a horizontal plane largely lowers, thereby degrading a commercial value of the resultant automotive vehicle.
In view of the above, it has been eagerly desired in an automotive industry to obtain a paint film arrangement exhibiting both high edge corrosion resistance and high external appearance.
SUMMARY OF THE INVENTION
As a result of a variety of researches and developments for paint film arrangements exhibiting high edge corrosion resistance and high external appearance, the inventors have experimentally found that the PGD value on a horizontal plane is lowered while no change of the same value is made on a vertical plane, in a painting system which is constituted by coating conventional intermediate and finish coat paints on the surface of an electrodeposition paint film whose flowability is lowered (See Comparative Examples 1 and 2). They have taken this into consideration, with the relationship between the degrees of deterioration of smoothness (due to run) on the vertical plane and the hardening starting time measured by the OPA. As a result, it has been confirmed that in a case of the intermediate coat paint having a hardening starting time not more than 20 minutes, the PGD value on the vertical plane after coating of the finish coat paint is the same as in a case in which the conventional intermediate coat paint is used (See Comparative Examples 1 to 10).
Besides, it has been confirmed that the same result is obtained for the vertical plane even in a case of using a low flowability electrodeposition paint; however, the PGD value on the horizontal plane is different according to the used electrodeposition paints and intermediate coat paints (See Comparative Examples 1 to 25).
The inventors' researches and developments taking account of the above-discussed experimental results have found the following facts: In case of using an intermediate coat paint having a hardening starting time not more than 15 minutes measured by the OPA, the PGD value of the finish coat paint on a vertical plane is about the same as in the conventional paint film arrangement. Additionally, in the case of using an intermediate coat paint having the hardening starting time not less than 15 minutes, it is very high in an ability to erase a roughness not less than 0.5 mm in wave length, in the surface of the electrodeposition paint. Even in the case of using a manner to previously reduce with the electrodeposition paint of a roughness not more than 0.5 mm in wavelength which is impossible to be erased even by the above intermediate coat paint, it has been found that an electrodeposition paint high in the edge corrosion resistance can be obtained. The present invention has been reached on the basis of the above-discussed newly founded knowledge.
A paint film arrangement of the present invention is comprised of a film of an electrodeposition paint. The surface of the film has a center line average height Ra within a range of 0.3 μ≦Ra≦0.8 μ. The total of values of power spectrum within a wavelength range not less than 0.5 mm of the surface is not more than 80 μV2. Additionally, a film of an intermediate coat paint is formed on the surface of the electrodeposition paint film. The intermediate coat paint film has a hardening starting time ranging from 15 to 20 minutes. The hardening starting time is determined according to a logarithmic decrement of viscoelasticity of the intermediate coat paint film by an oscilated pendulum type viscoelasticity measuring device.
Accordingly, the paint film arrangement of the present invention can be improved in both edge corrosion resistance of a steel plate and finished external appearance of the painted steel plate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a graph showing total of values of power spectrum of an electrodeposition paint film forming part of a paint film arrangement according to the present invention; and
FIG. 2 is a graph showing the relationship between time and logarithmic decrement, for the purpose of determining the hardening starting time t of an intermediate coat paint film forming part of the paint film arrangement according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
According to the present invention, a paint film arrangement is comprised of a film of an electrodeposition paint, the surface of the film having a center line average height Ra within a range of 0.3 μ≦Ra≦0.8 μ, total of values of power spectrum within a wavelength range not less than 0.5 mm of said surface being not more than 80 μV2 ; and a film of an intermediate coat paint formed on the electrodeposition paint film, the intermediate coat film having a hardening starting time ranging from 15 to 20 minutes, said hardening starting time being determined according to a logarithmic decrement of the intermediate coat paint film by an oscillated pendulum type viscoelasticity measuring device.
As mentioned above, according to the present invention, the surface of the electrodeposition paint film necessarily has a center line average height Ra not less than 0.3 μ, measured with a cutoff wavelength of 0.8 mm in order to obtain a high edge corrosion resistance. Besides, from the view point of the finishing condition with an intermediate coat paint, the maximum value of the center line average height Ra must be suppressed at a value of 0.8 μ. Additionally, the total (ΣP0.5 mm>) of the power spectrums within the wavelength not more than 0.5 mm according to a surface frequency analysis is decided to be not more than 80 μV2. The reasons why the surface condition of the electrodeposition paint is defined by the above-mentioned two values Ra and ΣP0.5 mm> is that the surface condition of the intermediate paint film depends not only on a surface roughness value Ra but also on another surface roughness value ΣP0.5 mm>. In other words, although the values Ra are the same in two cases, the electrodeposition paint surface conditions after coating the intermediate coat paint film may be different from each other, and depends on the difference in the surface roughness value ΣP0.5 mm>.
The values Ra and ΣP0.5 mm> are evaluation criteria for surface roughness within different wavelength ranges. The value Ra represents the surface roughness (average amplitude value) within a wavelength range from 0.8 to 0.5 mm, while the value of ΣP0.5 mm> represents the surface roughness (total of the square of amplitude value of the respective wavelength). Thus, the values Ra and ΣP0.5 mm are essential to find and define the feature of the surface profile of the coated paint film.
The value Ra is defined to be 0.8 μ in maximum for the reasons set forth below. The value Ra of the electrodeposition paint film surface is in a good interelationship to the hardening starting time of the intermediate coat paint film, measured by an Oscillated Pendulum Analysis (OPA). More specifically, in the case of an intermediate coat paint film (a conventional intermediate coat paint film) having the hardening starting time of 12 to 15 minutes, it is possible to smoothen the surface of the electrodeposition paint film surface having the surface roughness up to 0.3 μ. In case of the intermediate coat paint film having the hardening starting time of 15 to 20 minutes, it is possible to smoothen the surface of the electrodeposition paint film surface having the surface roughness not less than 0.8 μ. In case of an intermediate coat paint film having a hardening starting time not less than 20 minutes, smoothnening the surface roughness over 0.8 μ of the electrodeposition paint film is possible; however, a surface condition on a vertical plane is degraded owing to run of the intermediate coat paint. Therefore, the value Ra of the electrodeposition paint film is decided to be up to 0.8 μ, and the hardening starting time of the intermediate coat paint film is decided to be within a range from 15 to 20 minutes.
The value ΣP0.5 mm> is decided to be not more than 80 μV2 for the following reasons: Only the electrodeposition paint film having the surface roughness not more than 80 μV2 can be smoothened with the intermediate coat paint having the hardening starting time ranging from 15 to 20 minutes. It will be understood that it is impossible to smoothen the electrodeposition paint film having the surface roughness over 80 μV2 with the intermediate coat paint.
The analysis for the characteristics of the paint films will be discussed hereinafter with reference to FIGS. 1 and 2.
(1) Determination of Center Line Average Height (Roughness) Ra
The center line average height Ra was measured with a cutoff wavelength of 0.8 mm by using a commercially available surface roughness tester and according to a test method of JIS (Japanese Industrial Standard) B0601. The used tester was a Surfcom 550A produced by Tokyo Seimitsu Co., Ltd in Japan.
(2) Determination of Power Spectrum and Total thereof ΣP0.5 mm>
The power spectrum was able to be easily determined by combining the commercially available surface roughness tester and a FFT (Fast Fourier Transfer) analyzer. In this case, the Surfcom 550A was combined with a commercially available VS 3321A type FFT analyzer produced by Matsushita Communication Industrial Co., Ltd. in Japan.
The power spectrum was determined under conditions of input sensitivity of wavelength: -20 dB, frequency: not more than 100 Hz, and data input number (FFT data processing number): 1,024 points. Measurement was made 10 times, and an average for the 10 measurements was determined to obtain the power spectrum.
ΣP5 mm> was obtained by accumulating the values of the power spectrum within a wavelength not more than 0.5 mm which is a value obtained by dividing the frequency 1.2 Hz by a waveshape input rate (0.6 mm/s in this measurement). The relationship between the spectrum value and the wavelength is shown in FIG. 1. This determining method of the power spectrum and the accumulated value thereof are well known for a method of analyzing a surface profile of a paint film and was disclosed in a technical literature "Colouring Material Study Representation Summary (1985)" issued in Japan.
(3) Determination of Hardening Starting Time of Intermediate Coat Paint
The viscoelasticity of the intermediate coat paint was measured by an oscillated pendulum type viscoelasticity measuring device (trade name "Rheo-Vibron DDV-OPA") produced by Orientec Corporation in Japan, under conditions of a weight: 22 g, moment of inertia: 859 g.cm2, and temperature rising rate: 20° C./min. In the course of this viscoelasticity measurement, a time duration t between a time point of starting heating and a time point of starting in rise of a logarithmic decrement λ of viscoelasticity as shown in FIG. 2 was determined to obtain the hardening starting time. FIG. 2 illustrates a method for determining the hardening starting time t for the intermediate coat paint.
In order to evaluate the paint film arrangement of the present invention, production of the electrodeposition paint and the intermediate coat paint and Examples and Comparative Examples obtained by combining above paints will be discussed hereinafter.
Production of Electrodeposition Paint
A variety of electrodeposition paints were prepared by changing the ratio of a low temperature hardening resin and the concentration of pigment to regulate the flowability in a molten state.
Epoxidated polybutadiene containing double bonds was used as the low temperature hardening resin and prepared as set forth below.
First, an epoxidated polybutadiene was prepared as follows: Low polymerization of butadiene was made at 30° C. in the presence of toluene (a chain transfer agent) using benzyl sodium as a catalyst, thereby to obtain liquid polybutadiene which had a number average molecular weight of 2000, a viscosity of 120 poise at 25° and 65% of 1,2-bond. The liquid polybutadiene was epoxidated with peracetic acid thereby to produce an epoxidated polybutadiene having an oxyrane oxygen content of 6.0% by weight.
Next, the low temperature resin (the epoxidated polybutadiene containing double bonds) was prepared as follows: 1076 g of the epoxidated polybutadiene produced in the above-manner was mixed with 215 g of ethylcellosolve and supplied into a 2 liter autoclave. Thereafter, 50 g of dimethylamine was supplied into the autoclave. Then reaction was made at 150° C. for 5 hours. After unreacted amine was removed, a mixture of 83 g of acrylic acid, 7 g of hydroquinone and 27 g of ethylcellosolve was added into the autoclave. A further reaction was made at 150° C. for 45,minutes thereby producting a resin composition of the low temperature hardening resin having an amine value of 40 mgKOH/g, an acid value of 1 mg KOH/g and a solid concentration of 83.3% by weight.
An epoxy resin-acrylic acid addition resin for the purpose of controlling the ratio of the above mentioned low temperature hardening resin was prepared as follows: Bisphenol type epoxy resin (Epikote No. 1001, trade name of Shell Kagaku K.K. in Japan) having an epoxy equivalent of 500 was obtained by reaction between bisphenol A and epichlorohydrin and represented by the following chemical formula: ##STR1##
1000 g of the bisphenol type epoxy was desolved in 227 g of ethylcellosolve. In the ethylcellosolve containing the epoxy resin, 137 g of acrylic acid, 0.2 g of hydroquinone and 5 g of N, N-dimethylaminoethanol were added. Then, reaction was made at 100° C. for 5 hours thereby obtaining ethylcellosolve solution of the epoxy resin acrylic acid addition resin.
The above-discussed methods of production of the epoxidated polybutadiene, the low temperature hardening resin and the epoxy resin-acrylic acid addition resin are disclosed in Japanese Patent Publication No. 62-61077.
With the ethylcellosolve solution of epoxy resin-acrylic acid addition resin, the ratio between the low temperature hardening resin (R-1) and the ethylcellosolve solution of epoxy resin-acrylic acid addition resin (R-2) was controlled to have ratios (R-1)/(R-2)=0/1, 1/1, 2/1, and 5/1, thereby preparing four kinds of liquid resin mixtures. It is to be noted that in case of (R-1)/(R-2)=0/1, polyisocyanate compound (produced by Mobay Chemical Co., Ltd.) was mixed in a manner that 1.2 equivalent of NCO was relative to 1 equivalent of 0H group of (R-2).
In order to control a pigment concentration, carbon black, lead oxide, and TiO2 were added to the above-mentioned four kinds of liquid resin mixtures in a manner to have P(Pigment)/B(Binder) ratio or solid content ratio of 0.1, 0.2, 0.3 and 0.4, thereby preparing sixteen kinds of electrodeposition paints according to the following method:
500 g of low temperature hardening resin (R-1) and 100 g of the epoxy resin-acrylic acid addition resin ethylcellosolve solution (R-2) were supplied into a 2 liter separable flask and stirred at 80° C. for 1 hour. Thereafter, the content of the flask was cooled to room temperature. 10.6 g of acetic acid was added to the content to neutralize the content. Furtheremore, deionized water was added to the content to control the solid concentration thereby to prepare an aqueous solution having a solid concentration of 30% by weight.
250 g of the above aqueous solution, 20.8 g of carbon black, 104.2 g of lead oxide and 375 g of glass beads were supplied into a 1 liter stainless-steel beaker and vigorously stirred for 2 hours by using a high speed rotation mixer. Thereafter the glass beads were filtered thereby to prepare a pigment paste.
50 g of the above pigment paste and 900 g of the above-mentioned aqueous solution having the solid concentration of 30% by weight were supplied to a 2 liter glass beaker. Then 1035 g of deionized water containing 2.5 g of manganese acetate was added to the content in the glass beaker thereby preparing an electrodeposition paint.
                                  TABLE 1                                 
__________________________________________________________________________
Production                                                                
No.   1  2  3  4  5  6  7  8  9  10 11 12 13 14 15 16                     
__________________________________________________________________________
(R-1)/(R-2)                                                               
      0/1                                                                 
         0/1                                                              
            0/1                                                           
               0/1                                                        
                  1/1                                                     
                     1/1                                                  
                        1/1                                               
                           1/1                                            
                              2/1                                         
                                 2/1                                      
                                    2/1                                   
                                       2/1                                
                                          5/1                             
                                             5/1                          
                                                5/1                       
                                                   5/1                    
P/B   0.1                                                                 
         0.2                                                              
            0.3                                                           
               0.4                                                        
                  0.1                                                     
                     0.2                                                  
                        0.3                                               
                           0.4                                            
                              0.1                                         
                                 0.2                                      
                                    0.3                                   
                                       0.4                                
                                          0.1                             
                                             0.2                          
                                                0.3                       
                                                   0.4                    
__________________________________________________________________________
Production of Intermediate Paint
First, a resin solution of polyester resin modified by ε-caprolactone was produced as follows:
Starting materials are listed below.
______________________________________                                    
Isophthalic acid    66.45 parts                                           
Adipic acid         14.62 parts                                           
Tetrachlorophtalic anhydride                                              
                    15.20 parts                                           
Trimethylpropane    10.14 parts                                           
Neopentyl glycol    43.02 parts                                           
1, 6-hexanediol     26.41 parts                                           
ε-caprolactone                                                    
                    17.30 parts                                           
Total               193.17 parts                                          
______________________________________                                    
The above-mentioned five kinds of the above-listed starting materials except for tetrachlorophthalic anhydride and ε-caprolactone were supplied to a chemical reactor equipped with a heating device, a stirring device, a recirculating device, a water separator, a rectifying device, and a thermometer, and were heated. When the starting materials were molten to such an extent that stirring was possible, stirring was started. The temperature in the reactor was raised to 200° C., in which temperature rise was made at a constant temperature raising rate during a time lapse of 3 hours within a temperature range of from 160° to 220° C. Produced condensed water was removed from the reaction system. When the reaction temperature reached 220° C., hot insulation was made. 30 minutes after the hot insulation, 3 parts of xylol as a recirculation solvent was gradually added into the reactor, so that the reaction was changed to a condensation in the presence of the solvent, thus continuing the reaction. When a resin acid value had reached 2.0, the reaction was terminated and the reaction temperature was lowered to 100° C., so that a first polyester prepolymer was obtained.
Subsequently 15.20 parts of tetrachlorophthalic anhydride was supplied into the reactor. The temperature in the reactor was raised to 150° C. When the temperature had reached 150° C., hot insulation was made to continue the reaction. Time-lapse sampling was accomplished, maintaining the temperature 150° C. When the resin acid value was confirmed to be constant at 20, the reaction was terminated accomplishing cooling, thus obtaining a second polyester prepolymer.
Next 17.30 parts of ε-caprolactone was supplied to the reactor. The temperature in the reactor was raised to 150° C. When the temperature had reached 150° C., hot insulation was made to continue the reaction. Time lapse sampling was carried out maintaining the temperature of 150° C., tracing unreacted E-caprolactone by IR. The reaction was terminated at the time at which a conversion had reached a value not less than 98%. Then cooling was made. After cooling, 39.87 parts of xylol was added, thereby obtaining the resin solution of polyester resin modified by ε-caprolactone. The solution had a non-volatile content of 79.7% and a resin acid value of 18.6.
The above-discussed production method of the resin solution of polyester resin modified by ε-caprolactone is disclosed in Japanese Patent Provisional Publication No. 61-209278.
The thus produced resin solution of polyester resin modified by ε-caprolactone was mixed with melamine resin, controlling a blending ratio (the resin solution/melamine resin). The melamine resin was Cymel 303 (trade name of Mitsui Cyanamid Co., Ltd. in Japan). The intermediate coat paint was prepared according to the detail shown in Table 2. In Table 2, "Solvesso" is the trade name of a dilution thinner produced by Exxon Chemical Co., Ltd. and includes a high boiling point aromatic (petroleum) solvent as a major component. "Surface controlling agent" is a silicone additive produced by Toray Dowcorning Silicone Co., Ltd.
              TABLE 2                                                     
______________________________________                                    
Production No.                                                            
              17     18       19   20     21                              
______________________________________                                    
Titanium white                                                            
              63     63       63   63     63                              
Solution of polyester                                                     
              70     75       80   83     85                              
resin modified by                                                         
ε-caprolactone                                                    
(solid content 80 wt %)                                                   
Solvesso 150  14     14       14   14     14                              
Melamine resin                                                            
              30     25       20   17     15                              
Methanol      8      8        8    8      8                               
Surface controlling                                                       
              9      9        9    9      9                               
agent                                                                     
The solution of poly-                                                     
              2.3/1  3/1      4/1  4.9/1  5.7/1                           
ester resin/melamine                                                      
resin (solid content                                                      
ratio)                                                                    
Hardening starting time                                                   
              13     15       20   23     25                              
according to OPA (min)                                                    
______________________________________                                    
Preparation Method of Plate Coated with Electrodeposition Paint
Shot-dulled steel plates of SPCC (according to Japanese Industrial Standard) were chemically treated with PBL3020 (trade name of Nihon Parkerising Co., Ltd. in Japanese). The above-mentioned sixteen kinds of electrodeposition paints were coated respectively on the chemically treated steel plates by electrodeposition in a manner to obtain a coat film thickness of 20 μm under conditions of paint liquid temperature: 28° C., electrodeposition time: 3 minutes, and impressed voltage: 150 to 200 V Thereafter, thus coated paints were subjected to baking at 175° C. for 30 minutes thereby to harden the coated paint films.
Painting Method of Intermediate and Finish Coat Paints
The above-mentioned intermediate paints of Production Nos. 17 to 19 were coated on the above sixteen kinds of electrodeposition-coated steel plates by spray-painting to have a coat film thickness of 30 to 40 um. After allowing the plates to stand for a predetermined time, baking was made at 140° C. for 30 minutes. Subsequently, the respective steel plates coated with the intermediate paints were further coated with an alkyd resin finish coat paint (Melami No. 1500 black: trade name of Nihon Oil & Fats Co., Ltd.) to have a paint film thickness of 35 to 40 um. Then baking was made for each steel plate with the finish coat.
Examples 1 to 22 and Comparative Examples 1 to 25
Concerning a variety of painting systems as shown in Table 3, edge corrosion (rust) resistance and surface profile of the coated electrodeposition paint and finish condition after coating of the finish coat paint were evaluated. The result of the evaluation is shown Table 3. The painting systems of Comparative Examples 1 to 25 are not within the scope of the present invention, while the painting systems of Examples 1 to 22 are within the scope of the present invention. It is to noted that the Comparative Example 1 is a conventional painting system as discussed in the Description of the Prior Art. In Table 3, "flow intermediate coat" is an intermediate coat using an intermediate coat paint which has a good flowability during hardening under baking.
The edge corrosion resistance in Table 3 was measured by the following method: A steel cutter knife blade (LB-10: trade name of OLFA Corporation in Japan) was chemically treated with PBL3020. Each of the above-mentioned sixteen kinds of electrodeposition paints was coated on the chemically treated knife blade and thereafter coated with the electrodeposition paint. Then, the coated electrodeposition paint was baked at 175° C. for 30 minutes. Thereafter the knife blades coated with the electrodeposition paints were subjected to a salt water spraying test of 200 hours. After the test, the number of rusted points at the edge section was counted as shown in Table 3.
                                  TABLE 3                                 
__________________________________________________________________________
             Comparative Example                                          
Painting system                                                           
             1     2     3     4     5     6     7                        
__________________________________________________________________________
Surface profile of coated                                                 
electrodeposition paint                                                   
Production No.                                                            
             1     16    1     16    1     16    1                        
Ra (μ)    0.25  0.89  0.25  0.89  0.25  0.89  0.25                     
.sup.ΣP 0.5 mm> (μV2.sub.)                                       
             12    110   12    110   12    110   12                       
Hardening characteristics                                                 
of intermediate coat paint                                                
(hardening starting time                                                  
(min) by OPA)                                                             
Conventional Production                                                   
                   Production                                             
                         --    --    --    --    --                       
intermediate No. 17                                                       
                   No. 17                                                 
coat (12 min)                                                             
Flow intermediate                                                         
             --    --    Production                                       
                               Production                                 
                                     --    --    --                       
coat (15 min)            No. 18                                           
                               No. 18                                     
Flow intermediate                                                         
             --    --    --    --    Prodction                            
                                           Production                     
                                                 --                       
coat (20 min)                        No. 19                               
                                           No. 19                         
Flow intermediate                                                         
             --    --    --    --    --    --    Production               
coat (23 min)                                    No. 20                   
Flow intermediate                                                         
             --    --    --    --    --    --    --                       
coat (25 min)                                                             
Edge corrosion resistance                                                 
             100<  0-1   100<  0-1   100<  0-1   100<                     
(number of rusted points)                                                 
200 hr                                                                    
PGD value after coating                                                   
of finish coat paint                                                      
On horizontal plane                                                       
             0.85  0.60  0.85  0.60  0.85  0.60  0.85                     
On vertical plane                                                         
             0.50  0.50  0.50  0.50  0.50  0.50  Slight run               
                                                 occurred                 
                                                 (0.40)                   
__________________________________________________________________________
             Comparative Example                                          
Painting system                                                           
             8     9     10    11    12    13    14                       
__________________________________________________________________________
Surface profile of coated                                                 
electrodeposition paint                                                   
Production No.                                                            
             16    1     16    15    14    15    14                       
Ra (μ)    0.89  0.25  0.89  0.89  0.89  0.89  0.89                     
.sup.ΣP 0.5 mm> (μV2.sub.)                                       
             110   12    110   95    70    95    70                       
Hardening characteristics                                                 
of intermediate coat paint                                                
(hardening starting time                                                  
(min) by OPA)                                                             
Conventional --    --    --    Production                                 
                                     Production                           
                                           --    --                       
intermediate                   No. 17                                     
                                     No. 17                               
coat (12 min)                                                             
Flow intermediate                                                         
             --    --    --    --    --    Production                     
                                                 Production               
coat (15 min)                              No. 18                         
                                                 No. 18                   
Flow intermediate                                                         
             --    --    --    --    --    --    --                       
coat (20 min)                                                             
Flow intermediate                                                         
             Production                                                   
                   --    --    --    --    --    --                       
coat (23 min)                                                             
             No. 20                                                       
Flow intermediate                                                         
             --    Production                                             
                         Production                                       
                               --    --    --    --                       
coat (25 min)      No. 21                                                 
                         No. 21                                           
Edge corrosion resistance                                                 
(number of rusted points)                                                 
             0-1   100<  0-1   0-1   0-1   0-1   0-1                      
200 hr                                                                    
PGD value after coating                                                   
of finish coat paint                                                      
On horizontal plane                                                       
             0.75  0.85  0.75  0.65  0.70  0.70  0.75                     
On vertical plane                                                         
             Slight run                                                   
                   Run   Run   0.50  0.50  0.50  0.50                     
             occurred                                                     
                   occurred                                               
                         occurred                                         
             (0.40)                                                       
                   (0.35)                                                 
                         (0.35)                                           
__________________________________________________________________________
             Comparative Example                                          
Painting system                                                           
             15    16    17    18    19    20    21                       
__________________________________________________________________________
Surface profile of coated                                                 
electrodeposition paint                                                   
Production No.                                                            
             15    14    15    14    15    14    13                       
Ra (μ)    0.89  0.89  0.89  0.89  0.89  0.89  0.80                     
.sup.ΣP 0.5 mm> (μV2.sub.)                                       
             95    70    95    70    95    70    95                       
Hardening characteristics                                                 
of intermediate coat paint                                                
(hardening starting time                                                  
(min) by OPA)                                                             
Conventional --    --    --    --    --    --    Production               
intermediate                                     No. 17                   
coat (12 min)                                                             
Flow intermediate                                                         
             --    --    --    --    --    --    --                       
coat (15 min)                                                             
Flow intermediate                                                         
             Production                                                   
                   Production                                             
                         --    --    --    --    --                       
coat (20 min)                                                             
             No. 19                                                       
                   No. 19                                                 
Flow intermediate                                                         
             --    --    Production                                       
                               Production                                 
                                     --    --    --                       
coat (23 min)            No. 20                                           
                               No. 20                                     
Flow intermediate                                                         
             --    --    --    --    Production                           
                                           Production                     
                                                 --                       
coat (25 min)                        No. 21                               
                                           No. 21                         
Edge corrosion resistance                                                 
             0-1   0-1   0-1   0-1   0-1   0-1   0-1                      
(number of rusted points)                                                 
200 hr                                                                    
PGD value after coating                                                   
of finish coat paint                                                      
On horizontal plane                                                       
             0.75  0.80  0.80  0.80  0.80  0.80  0.75                     
On vertical plane                                                         
             0.50  0.50  Slight run                                       
                               Slight run                                 
                                     Run   Run   0.50                     
                         occurred                                         
                               occurred                                   
                                     occurred                             
                                           occurred                       
                         (0.40)                                           
                               (0.40)                                     
                                     (0.35)                               
                                           (0.35)                         
__________________________________________________________________________
             Comparative Example     Example                              
Painting system                                                           
             22    23    24    25    1     2      3                       
__________________________________________________________________________
Surface profile of coated                                                 
electrodeposition paint                                                   
Production No.                                                            
             13    13    13    13    2     2     3                        
Ra (μ)    0.80  0.80  0.80  0.80  0.30  0.30  0.38                     
.sup.ΣP 0.5 mm> (μV2.sub.)                                       
             95    95    95    95    18    18    22                       
Hardening characteristics                                                 
of intermediate coat paint                                                
(hardening starting time                                                  
(min) by OPA)                                                             
Conventional --    --    --    --                                         
intermediate                                                              
coat (12 min)                                                             
Conventional                         Production                           
                                           --    Production               
intermediate                         No. 18      No. 18                   
coat (15 min)                                                             
Flow intermediate                                                         
             Production                                                   
                   --    --    --                                         
coat (15 min)                                                             
             No. 18                                                       
Flow intermediate                                                         
             --    Production                                             
                         --    --    --    Production                     
                                                 --                       
coat (20 min)      No. 19                  No. 19                         
Flow intermediate                                                         
             --    --    Production                                       
                               --                                         
coat (23 min)            No. 20                                           
Flow intermediate                                                         
             --    --    --    Production                                 
coat (25 min)                  No. 21                                     
Edge corrosion resistance                                                 
             0-1   0-1   0-1   0-1   30-40 30-40 30-40                    
(number of rusted points)                                                 
200 hr                                                                    
PGD value after coating                                                   
of finish coat paint                                                      
On horizontal plane                                                       
             0.80  0.80  0.85  0.85  0.85  0.85  0.85                     
On vertical plane                                                         
             0.50  0.50  Slight run                                       
                               Run   0.50  0.50  0.50                     
                         occurred                                         
                               occurred                                   
                         (0.40)                                           
                               (0.35)                                     
__________________________________________________________________________
             Example                                                      
Painting system                                                           
             4     5     6     7     8     9     10                       
__________________________________________________________________________
Surface profile of coated                                                 
electrodeposition paint                                                   
Production No.                                                            
             3     4     4     5     5     6     6                        
Ra (μ)    0.38  0.40  0.40  0.51  0.51  0.55  0.55                     
.sup.ΣP 0.5 mm> (μV2.sub.)                                       
             22    29    29    50    50    55    55                       
Hardening characteristics                                                 
of intermediate coat paint                                                
(hardening starting time                                                  
(min) by OPA)                                                             
Conventional --    Production                                             
                         --    Production                                 
                                     --    Production                     
                                                 --                       
intermediate       No. 18      No. 18      No. 18                         
coat (15 min)                                                             
Flow intermediate                                                         
             Production                                                   
                   --    Production                                       
                               --    Production                           
                                           --    Production               
coat (20 min)                                                             
             No. 19      No. 19      No. 19      No. 19                   
Edge corrosion resistance                                                 
             30-40 5-10  5-10  1-5   1-5   0-1   0-1                      
(number of rusted points)                                                 
200 hr                                                                    
PGD value after coating                                                   
of finish coat paint                                                      
On horizontal plane                                                       
             0.85  0.85  0.85  0.85  0.85  0.85  0.85                     
On vertical plane                                                         
             0.50  0.50  0.50  0.50  0.50  0.50  0.50                     
__________________________________________________________________________
             Example                                                      
Painting system                                                           
             11    12    13    14    15    16    17                       
__________________________________________________________________________
Surface profile of coated                                                 
electrodeposition paint                                                   
Production No.                                                            
             7     7     8     8     9     9     10                       
Ra (μ)    0.57  0.57  0.57  0.57  0.60  0.60  0.68                     
.sup.ΣP 0.5 mm> (μV2.sub.)                                       
             70    70    80    80    30    30    50                       
Hardening characteristics                                                 
of intermediate coat paint                                                
(hardening starting time                                                  
(min) by OPA)                                                             
Conventional Production                                                   
                   --    Production                                       
                               --    Production                           
                                           --    Production               
intermediate No. 18      No. 18      No. 18      No. 18                   
coat (15 min)                                                             
Flow intermediate                                                         
             --    Production                                             
                         --    Production                                 
                                     --    Production                     
                                                 --                       
coat (20 min)      No. 19      No. 19      No. 19                         
Edge corrosion resistance                                                 
             0-1   0-1   0-1   0-1   0-1   0-1   0-1                      
(number of rusted points)                                                 
200 hr                                                                    
PGD value after coating                                                   
of finish coat paint                                                      
On horizontal plane                                                       
             0.85  0.85  0.85  0.85  0.85  0.85  0.85                     
On vertical plane                                                         
             0.50  0.50  0.50  0.50  0.50  0.50  0.50                     
__________________________________________________________________________
                         Example                                          
            Painting system                                               
                         18    19     20   21    22                       
__________________________________________________________________________
            Surface profile of coated                                     
            electrodeposition paint                                       
            Production No.                                                
                         10    11    11    12    12                       
            Ra (μ)    0.68  0.78  0.78  0.80  0.80                     
            .sup.ΣP 0.5 mm> (μV2.sub.)                           
                         50    58    58    80    80                       
            Hardening characteristics                                     
            of intermediate coat paint                                    
            (hardening starting time                                      
            (min) by OPA)                                                 
            Conventional --    Production                                 
                                     --    Production                     
                                                 --                       
            intermediate       No. 18      No. 18                         
            coat (15 min)                                                 
            Flow intermediate                                             
                         Production                                       
                               --    Production                           
                                           --    Production               
            coat (20 min)                                                 
                         No. 19      No. 19      No. 19                   
            Edge corrosion resistance                                     
                         0-1   0-1   0-1   0-1   0-1                      
            (number of rusted points)                                     
            200 hr                                                        
            PGD value after coating                                       
            of finish coat paint                                          
            On horizontal plane                                           
                         0.85  0.85  0.85  0.85  0.85                     
            On vertical plane                                             
                         0.50  0.50  0.50  0.50  0.5                      
__________________________________________________________________________

Claims (6)

What is claimed is:
1. A paint film arrangement comprising:
a film of an electrodeposition paint, surface of said film having a center line average height Ra within a range of 0.3 μ≦Ra≦0.8 μ, total of values of power spectrum within a wavelength range not more than 0.5 mm of said surface being not more than 80 μV2 ; and
a film of an intermediate coat paint, formed on said electrodeposition paint film, said intermediate coat paint film having a hardening starting time ranging from 15 to 20 minutes, said hardening starting time being determined according to a log arithmic decrement of viscoelasticity of the intermediate coat paint film by an oscillated pendulum type viscoelasticity measuring device.
2. A paint film arrangement as claimed in claim 1, wherein said electrodeposition paint includes epoxidated polybutadiene containing double bond, epoxy resin having added acrylic acid, and pigments.
3. A paint film arrangement as claimed in claim 1, wherein said intermediate coat paint includes polyester resin modified by ε-caprolactone, and melamine resin.
4. A paint film arrangement as claimed in claim 1, further comprising a film of a finish coat paint.
5. A paint film arrangement as claimed in claim 4, wherein said finish coat paint has a main component of alkyd resin.
6. An outer panel of an automotive vehicle, comprising:
a steel plate;
a film of an electrodeposition paint formed on a surface of said steel plate, a surface of said film having a center line average height Ra within a range of 0.3μ≦Ra≦0.8μ, total of values of power spectrum within a wavelength range not more than 0.5 mm of said surface being not more than 80 μV2 ;
a film of an intermediate coat paint formed on said electrodeposition paint film said intermediate coat paint film having a hardening starting time ranging from 15 to 20 minutes, said hardening starting time being determined according to a logarithmic decrement of the intermediate coat paint film by an oscillated pendulum type viscoelasticity measuring device; and
a film of a finish coat paint formed on a surface of said intermediate coat paint film.
US07/452,831 1988-12-28 1989-12-20 Paint film arrangement Expired - Fee Related US5124209A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP63329473A JPH0653265B2 (en) 1988-12-28 1988-12-28 How to paint car skins
JP63-329473 1988-12-28

Publications (1)

Publication Number Publication Date
US5124209A true US5124209A (en) 1992-06-23

Family

ID=18221771

Family Applications (1)

Application Number Title Priority Date Filing Date
US07/452,831 Expired - Fee Related US5124209A (en) 1988-12-28 1989-12-20 Paint film arrangement

Country Status (2)

Country Link
US (1) US5124209A (en)
JP (1) JPH0653265B2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20230113264A1 (en) * 2020-06-17 2023-04-13 Nippon Steel Corporation Electrical steel sheet, laminated core and rotating electric machine

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1243851A3 (en) * 1992-12-25 2002-11-06 Kawasaki Seitetsu Kabushiki Kaisha Heating apparatus including plurality of regenerative burner units and operating method thereof
JP2002224613A (en) * 2001-02-02 2002-08-13 Nippon Paint Co Ltd Method of forming multilayer coating film and multilayer coating film
JP7363589B2 (en) * 2020-03-04 2023-10-18 トヨタ自動車株式会社 Paint quality prediction device and trained model generation method

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61209278A (en) * 1985-03-14 1986-09-17 Nippon Paint Co Ltd Resin composition for intermediate coating
US4619746A (en) * 1985-10-02 1986-10-28 Ppg Industries, Inc. Process for topcoating an electrocoated substrate with a high solids fluid coating
US4711917A (en) * 1985-02-07 1987-12-08 Ppg Industries, Inc. Cationic coating compositions for electrodeposition over rough steel
US4761337A (en) * 1986-09-26 1988-08-02 Basf Corporation Cationic electrodepositable resin compositions containing polyurethane resin dispersions
JPH06261077A (en) * 1993-01-26 1994-09-16 Internatl Business Mach Corp <Ibm> Prioritizing method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4711917A (en) * 1985-02-07 1987-12-08 Ppg Industries, Inc. Cationic coating compositions for electrodeposition over rough steel
JPS61209278A (en) * 1985-03-14 1986-09-17 Nippon Paint Co Ltd Resin composition for intermediate coating
US4619746A (en) * 1985-10-02 1986-10-28 Ppg Industries, Inc. Process for topcoating an electrocoated substrate with a high solids fluid coating
US4761337A (en) * 1986-09-26 1988-08-02 Basf Corporation Cationic electrodepositable resin compositions containing polyurethane resin dispersions
JPH06261077A (en) * 1993-01-26 1994-09-16 Internatl Business Mach Corp <Ibm> Prioritizing method

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
"Colouring Material Study Representation Summary", (1985), (1A-9).
Colouring Material Study Representation Summary , (1985), (1A 9). *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20230113264A1 (en) * 2020-06-17 2023-04-13 Nippon Steel Corporation Electrical steel sheet, laminated core and rotating electric machine

Also Published As

Publication number Publication date
JPH02175239A (en) 1990-07-06
JPH0653265B2 (en) 1994-07-20

Similar Documents

Publication Publication Date Title
JPH0635561B2 (en) Coil coating coating composition
US5075165A (en) Composite paint film
DE3447257A1 (en) METHOD FOR THE MULTI-LAYER CATHODIC WET-IN-WET LACQUERING OF METALLICALLY CONDUCTIVE SUBSTRATES
US5124209A (en) Paint film arrangement
US4829132A (en) Resinous composition containing polyester resin, for coating use
JP3469792B2 (en) Paint composition and painted metal plate
JP4044167B2 (en) Coating composition and painted metal plate using the same
CN110431202A (en) Cation electric deposition paint composition
DE69825102T2 (en) COATING COMPOSITION FOR PRE-COATED STEEL PLATE, PRE-COATED STEEL PLATE AND METHOD FOR THE PRODUCTION THEREOF
JPH1119583A (en) Method for coating metal plate and metal plate coated by method thereof
JPH0448347B2 (en)
JPH058751B2 (en)
JP3204070B2 (en) Pre-coated steel sheet with excellent formability, which is used after applying the final coating after forming
JPH10330685A (en) Coating material composition and coated metallic plate using the same
JPH06313152A (en) Coating composition
US5183836A (en) Composite paint
EP0398756B1 (en) Composite paint film arrangement
JP2001029883A (en) Precoated steel sheet
JPH04176367A (en) Dull finish coated steel sheet excellent in workability
JP3490878B2 (en) Paint composition for curtain coating and curtain coating method using this composition
JP2000129207A (en) Resin composition for coating
JPS63258672A (en) Formation of film by two-coating and one-baking coating
JPH0144147B2 (en)
JPH0366746A (en) Polyester resin composition for paint and paint containing the same
JPS6129632B2 (en)

Legal Events

Date Code Title Description
AS Assignment

Owner name: NISSAN MOTOR CO., LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:KISHI, HIROYUKI;KIMURA, HITOSHI;SAKAUCHI, TSUNEO;AND OTHERS;REEL/FRAME:005254/0936;SIGNING DATES FROM 19900129 TO 19900131

AS Assignment

Owner name: NISSAN MOTOR CO., LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:KISHI, HIROYUKI;KIMURA, HITOSHI;SAKAUCHI, TSUNEO;AND OTHERS;REEL/FRAME:005751/0776

Effective date: 19910523

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
FP Lapsed due to failure to pay maintenance fee

Effective date: 20000623

STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362